Spray gun

ABSTRACT

A piston pump spray gun with a detachable container for fluids, such as paint, to be sprayed is provided with a removable die cast metal or injection molded plastics one-piece pump housing and lid or cover for the container with the pump housing portion molded or cast around a hard metal cylinder sleeve for the piston and passages connecting the interior of the sleeve with the container without requiring seals to feed liquid from the container to the pump and for draining liquid back to the container. The one-piece part together with a piston operating in the cylinder sleeve is easily mounted on and removed from the main body of the spray gun by means of a single securing ring rotatable on the pump housing portion and threaded in the front of the main body of the gun. The one-piece molding or casting with its integrated hard metal cylinder eliminates leakage paths, reduces manufacturing costs, and facilitates replacement or repair of worn or broken parts.

United States Patent Wagner Aug. 12, 1975 SPRAY GUN Primary ExaminerM.Henson Wood, Jr. [76] Inventor: Josef Wagner, Markdorfer Strasse Assmamm M l Mar 185, 799 Friedrichshafen 2 Attorney, Agent, or FzrmH1ll,Gross, Simpson, Van Germany Santen, Steadman, Chiara & Simpson 22 Filed:June 13, 1974 v 21 1 Appl. No.: 478,856

[30] Foreign Application Priority Data [5 7 ABSTRACT A piston pump spraygun with a detachable container for fluids, such as paint, to be sprayedis provided with a removable di cast metal or injection molded plasticsone-piece pump housing and lid or cover for the container with the pumphousing portion molded or cast around a hard metal cylinder sleeve forthe piston and passages connecting the interior of the sleeve with thecontainer without requiring seals to feed liquid from the container tothe pump and for draining liquid back to the container. The one-piecepart together with a piston operating in the cylinder sleeve is easilymounted on and removed from the main body of the spray gun by means of asingle securing ring rotatable on the pump housing portion and threadedin the front of the main body of the gun. The one-piece molding orcasting with it's integrated hard metal cylinder eliminates leakagepaths, reduces manufacturing costs, and facilitates replacement orrepair of worn or broken parts.

10 Claims, 3 Drawing Figures PATENTED 3.899.134

SHEET 1 FIG] PATENTEBAUB1 21975 3, 899, 1 34 SHEEI 2 SPRAY GUNBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to the art of spray guns and particularly to a simplified,inexpensive one-piece molded or cast part for a piston pump supplycontainer carrying spray gun surrounding and integrating a hard metalcylinder sleeve for the piston and providing a mounting cover or lid forthe container. Specifically, the one-piece part of this inventionprovides a pump housing portion molded or cast around a cylinder sleevein which the piston operates and a depending cover or lid portion intowhich is threaded a container for material to be sprayed and having leakproof passages conveying fluid between the container and sleeve withoutthe aid of seals. The piston housing portion of the part carries alocking ring which is threaded into the spray gun housing for securingthe part to the spray gun.

2. Prior Art Piston pump paint spray guns have heretofore been providedwith piston cylinders or sleeves inserted in a bore or recess in thespray gun housing and secured therein by a threaded pin. Suchconstructions required seals between the cylinder sleeve, the bore inwhich the sleeve was received, and the structural part providing thebore. These seals had to be seated in recesses and not only were extraseal parts required, but additional machining was necessary. Then whenthe cylinder sleeve was replaced, satisfactory rescaling was frequentlynot obtained so that air would be sucked into the piston pump and feedperformance would be impaired.

SUMMARY OF THIS INVENTION The present invention now eliminates theheretofore required seals and extra machining operations for piston pumpspray guns by molding or die casting the pump housing around thecylinder sleeve for the piston and integrating this housing with adepending lid or cover for the spray gun supply container. The onepiecepump housing and lid molded or cast part has a hollow stem receiving asuction tube depending into the container which registers with anaperture in the cylinder sleeve to feed the liquid to be sprayed to thepump and also has a passageway communicating with a chamber in thesleeve to drain liquid back to the container. Machining of the passagesand seals between these passages and the cylinder sleeve are not neededbecause the pump housing part is tightly molded around and integratedwith the cylinder sleeve.

The one-piece molded or die cast part is detachably mounted on the mainhousing of the spray gun with the pump housing portion of the parthaving a cylindrical sleeve fitting into a bore of the gun housing andthe lid portion of the part underlying the housing while a neckconnecting the pump housing and lid portions of the part fits in an openfront recess in the bottom of the housing bore. A single locking ring onthe pump housing portion is threaded into the bore of the gun housing tosecure the part in position in the gun housing. A spray head is threadedon the outer end of the pump housing portion of the part and an outletvalve slidable in the pump housing portion seats against an end of thecylinder sleeve while a piston slidable in the sleeve is reciprocated bydriving means in the gun housing to suck liquid from the container intothe cylinder sleeve and to discharge the liquid from the sleeve throughthe outlet valve to the spray nozzle.

It is then an object of this invention to simplify and reduce the costof piston pump spray guns by molding or die casting a pump housingaround a cylinder sleeve for the pump.

Another object of the invention is to eliminate heretofore requiredseals between the pump housing and cylinder sleeve of a piston pumpspray gun.

Another object of the invention is to provide a spray gun with aremovable molded or die cast part housing a piston pump assembly andsuspending a supply container from the gun.

A further object of the invention is to provide a spray gun for theatomization of liquids by means of a piston pump driven from analternating current oscillating magnet and having a supply containersuspended therefrom wherein a one-piece molded or cast part provides thepump housing and the lid for the supply container and is removable fromthe gun by manipulation of a single locking member.

Another object of the invention is to provide a piston pump spray gunhaving a housing with an open front bore and an open front bottom recessdetachably receiving a one-piece part including a pump housing fittingsaid bore, a neck fitting said recess, and a lid suspended from saidneck underlying the gun housing to support and close the top of a supplycontainer.

Other and further objects of this invention will become apparent tothose skilled in this art from the following detailed description of theannexed sheets of drawings which by way of example only, illustrate oneembodiment of the invention.

IN THE DRAWINGS FIG. 1 is a side elevational view of a spray gunprovided with the pump part of this invention and shown partly invertical section;

FIG. 2 is an enlarged vertical sectional view of the pump and containerlid part provided for the spray gun of FIG. 1 according to thisinvention; and

FIG. 3 is a front end elevational view with parts in transverse sectionof the spray gun of FIG. I.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT The spray gun I of FIG. 1is especially suitable for paint spraying and includes a gun housing 2in which is mounted an electromagnet 3 with an oscillating armature 4actuated by alternating current from a switch 5 in a depending handleportion of the housing 2. A supply container 6 is removably suspendedfrom the housing 2 and feeds liquids, such as paint, through a suctiontube 7 suspended from a cover or lid 8 for the container 6. The lid 8 isa portion of a one-piece injection molded plastics material or die castmetal part suspended from a bore 9 of the gun housing 2 and has asleeve-like pump housing portion 10 removably seated in the bore 9 andmolded or cast around a hard metal cylinder sleeve 11.

As shown in FIG. 1, a piston 12 is slidably mounted in the cylinder 11and a pumping chamber 13 is provided ahead of this piston 12. A returnspring 14 in the bore 9 of the gun housing 2 biases the piston 12against the armature 4.

municates the outlet valve with the spray nozzle 16.

The lid or cover portion 8 and the pump housing portion 10 of theone-piece molded or die cast part are joined by a neck 21 fitting snuglyin an open front bottom recess 22 in the bore 9 of the gun housing 2 anda flat bottom wall 23 of the gun housing receives the flat top of thecover or lid snugly thereagainst with the periphery of the top of thelid being bottomed against a shoulder 24 acting as a stop member on thebottom of the gun housing 2.

A hollow stem 25 depends from the lid and has a tapered boretherethrough receiving the suction tube 7. A passageway 26 is alsoprovided through the lid and neck 21 adjacent this stem 25. The hollowinterior of the stem 25 is connected through an aperture 27 in thecylinder sleeve 11 with the pumping chamber 13 of the sleeve. An opening28 in the sleeve 11 joins the passageway 26 with an enlarged internalcollection cham ber 29 in the sleeve 11.

The sleeve has an annular recess 30 therearound filled with plastics ormetal material from the molding or die casting operation to integrallylock the sleeve with the pump housing portion 10. The bore 9 of the gunhousing 2 has an internal shoulder 31 forming an abutment for an annularcollar 32 integral with the pump housing portion 10 to limit theinsertion of this pump housing portion 10 in the bore 9.

A securing ring 33 rotatable on the outer end of the pump housing 10 isscrewed into an internal thread 34 in the outer end of the bore 9against the collar 32 to secure the collar against the shoulder 31. Thusthe pump housing 10 is tightly anchored in the bore 9.

The spray nozzle 16 is threaded on the projecting front end portion 35of the pump housing 10 which has external threads 36 for receiving theinternal threads of the nozzle 16.

Container 6 has an externally threaded neck threaded in the internalthread 37 of the cover or lid 8, to provide a liquid-tight connectionbetween the container and cover so that liquid will not spill out of thecontainer even when the spray gun has fallen over or is laid down.

In operation of the spray gun I, the handle portion of the gun housing 2is manually gripped and the switch 5 is depressed by the index finger ofthe gripping hand whereupon the electromagnet 3 will be energized tooscillate the armature 4 thereby driving the piston 12 to the left asviewed in FIG. 1 and displacing liquid in the pumping chamber 13 tounseat the outlet valve 15 and discharge the liquid through the nozzle16. On this pressure stroke of the piston 12, the inlet aperture 27 isclosed by the piston. As the armature 4 swings to the right, the spring14 causes the piston to follow the armature thereby retracting thepiston to the right on a suction stroke closing the outlet valve 15,uncovering the aperture 27 and sucking liquid from the container 6through the tube 7 into the pumping chamber 13. Liquid finding its waybetween the piston 12 and the cylinder 1 l is collected in the enlargedcollection chamber 29 and drained back to the container 6 through theopening 28 and the passageway 26.

When it is desired to replace or repair the piston pump or any of itscomponents, the securing ring 33 is unthreaded from the threads 34 andthe entire pump assembly is easily pulled forwardly out of the gunhousing since the pump housing, and the lid or cover 8 are all part ofthe same one-piece member. Then it is easy to remove the piston, thevalve, and the spring of the pump assembly for repair, or replacement.Cleaning of the pump components is, of course, also facilitated.

Therefore, from the above descriptions it will be clearly understoodthat this invention provides a simplifled, inexpensive pump assembly forpiston pump spray guns which is easily mounted in and removed from thespray gun housing and eliminates heretofore necessary seals andmachining operations. The one-piece molded plastics or metal die castpart of this invention for mounting the pump components and suspendingthe supply container for the gun is inexpensive and easily formed arounda hard wear resisting cylinder sleeve for the piston by injectionmolding, metal spray die casting and the like forming operations.

I claim as my invention:

l. A piston pump spray gun which comprises a housing having a dependinghandle, an electromagnetic motor with an oscillating armature in saidhousing, a switch in said handle controlling current flow to said motor,said housing having a bore communicating with said armature and with thefront of the housing, a onepiece part having a pump housing sleevefitting said bore with a hard metal cylinder sleeve therein, a pistonslidable in said cylinder sleeve, a spring in said bore of the gunhousing biasing said piston against said oscillating armature of saidmotor, an outlet valve in said pump housing sleeve portion bottomedagainst said cylinder sleeve, a spray nozzle on the outer end of saidpump housing sleeve receiving fluid from said outlet valve, a lockingring rotatable on said pump housing sleeve threaded in said gun housingbore against said pump housing sleeve for securing the sleeve in thebore, said sleeve having a depending neck and a container coversuspended on said neck, said gun housing having a recess receiving saidneck and a bottom wall receiving said cover, a removable liquidscontainer suspended from said cover, said neck and cover having passagestherethrough connecting the interior of the container with the interiorof said cylinder sleeve, a suction tube extending from one of saidpassages to the bottom of said container and a collection chamber insaid cylinder sleeve communicating with the other of said passageswhereby said spring and said armature will reciprocate said piston tosuck liquid from said container through said tube into said cylindersleeve and will discharge the liquid in the sleeve past said outletvalve to said spray nozzle and said part is easily mounted in andremoved from the bore and recess of said gun housing by manipulation ofsaid locking ring.

2. The spray gun of claim 1 wherein said one piece part has a dependinghollow stem receiving said suction tube.

3. The spray gun of claim 1 wherein the bore of the gun housing iscylindrical, the pump housing sleeve portion of the part snugly fitssaid bore and the recess of the gun housing is open at the front andsnugly receives the neck of said part.

4. The spray gun of claim 1 wherein the pump housing portion of saidpart is integrally molded around said sleeve and said sleeve has anexternal groove receiving a portion of the molded pump housing portion.

5. in a piston pump spray gun having a housing, a motor in the housingfor driving the piston pump and a depending container for material to besprayed suspended from the housing, the improvements of a onepiece parthaving a pump housing portion fitting in said spray gun housing andintegrally molded around a hard metal cylinder sleeve for the piston ofthe piston pump and a cover portion depending therefrom supporting saidcontainer with passageways connecting the container with the interior ofthe cylinder sleeve, and a locking means detachably securing saidone-piece part to said spray gun housing.

6. The spray gun of claim 5 wherein the pump housing portion of theone-piece part is cylindrical and sized for snug fitting in the spraygun housing and a spray nozzle is secured on the end of said pumphousing cylindrical portion.

7. The spray gun of claim 5 wherein the locking means is rotatablymounted on the pump housing portion of the one-piece part.

8. in a spray gun of the type having a motor housing, a motor in thehousing, a piston pump driven by the motor in the housing and acontainer suspended from the housing to supply liquid to be sprayed tothe pump together with a spray nozzle discharging the liquid from thepump, the improvements which comprise said housing having a bore openingadjacent said nozzle, a one-piece part having a portion removablyinsertable in said bore of the housing and molded around a cylindersleeve forming the cylinder for the piston pump together with a coverportion depending therefrom supporting the container for the liquid tobe sprayed and having passages connecting the container with thecylinder sleeve, and a locking ring rotatable on the onepiece partthreaded in said bore of the housing releasably securing said one-piecepart to said housing.

9. The spray gun of claim 8 wherein the portion of the one-piece partinsertable in the bore of the housing has a front end projecting fromthe housing and a spray nozzle is removably secured on said front end.

10. A one-piece cast or molded part for removable attachment to thehousing of a spray gun having a supply container which comprises amember having a sleeve portion insertable in a spray gun housingproviding a pump housing and surrounding a pump cylinder sleeve inintegrated relationship therewith together with a depending neck portionsuspending a lid adapted to receive and support the supply container forthe gun, said member having passages therethrough joining the interiorof the cylinder sleeve with the interior of said lid, and a lockingmember on said one-piece part for detachably uniting the part to thespray gun.

1. A piston pump spray gun which comprises a housing having a dependinghandle, an electromagnetic motor with an oscillating armature in saidhousing, a switch in said handle controlling current flow to said motor,said housing having a bore communicating with said armature and with thefront of the housing, a one-piece part having a pump housing sleevefitting said bore with a hard metal cylinder sleeve therein, a pistonslidable in said cylinder sleeve, a spring in said bore of the gunhousing biasing said piston against said oscillating armature of saidmotor, an outlet valve in said pump housing sleeve portion bottomedagainst said cylinder sleeve, a spray nozzle on the outer end of saidpump housing sleeve receiving fluid from said outlet valve, a lockingring rotatable on said pump housing sleeve threaded in said gun housingbore against said pump housing sleeve for securing the sleeve in thebore, said sleeve having a depending neck and a container coversuspended on said neck, said gun housing having a recess receiving saidneck and a bottom wall receiving said cover, a removable liquidscontainer suspended from said cover, said neck and cover having passagestherethrough connecting the interior of the container with the interiorof said cylinder sleeve, a suction tube extending from one of saidpassages to the bottom of said container and a collection chamber insaid cylinder sleeve communicating with the other of said passageswhereby said spring and said armature will reciprocate said piston tosuck liquid from said container through said tube into said cylindersleeve and will discharge the liquid in the sleeve past said outletvalve to said spray nozzle and said part is easily mounted in andremoved from the bore and recess of said gun housing by manipulation ofsaid locking ring.
 2. The spray gun of claim 1 wherein said one piecepart has a depending hollow stem receiving said suction tube.
 3. Thespray gun of claim 1 wherein the bore of the gun housing is cylindrical,the pump housing sleeve portion of the part snugly fits said bore andthe recess of the gun housing is open at the front and snugly receivesthe neck of said part.
 4. The spray gun of claim 1 wherein the pumphousing portion of said part is integrally molded around said sleeve andsaid sleeve has an external groove receiving a portion of the moldedpump housing portion.
 5. In a piston pump spray gun having a housing, amotor in the housing for driving the piston pump and a dependingcontainer for material to be sprayed suspended from the housing, theimprovements of a one-piece part having a pump housing portion fittingin said spray gun housing and integrally molded around a hard metalcylinder sleeve for the piston of the piston pump and a cover portiondepending therefrom supporting said container with passagewaysconnecting the container with the interior of the cylinder sleeve, and alocking means detachably securing said one-piece part to said spray gunhousing.
 6. The spray gun of claim 5 wherein the pump housing portion ofthe one-piece part is cylindrical and sized for snug fitting in thespray gun housing and a spray nozzle is secured on the end of said pumphousing cylindrical portion.
 7. The spray gun of claim 5 wherein thelocking means is rotatably mounted on the pump housing portion of theone-piece part.
 8. In a spray gun of the type having a motor housing, amotor in the housing, a piston pump driven by the motor in the housingand a container suspenDed from the housing to supply liquid to besprayed to the pump together with a spray nozzle discharging the liquidfrom the pump, the improvements which comprise said housing having abore opening adjacent said nozzle, a one-piece part having a portionremovably insertable in said bore of the housing and molded around acylinder sleeve forming the cylinder for the piston pump together with acover portion depending therefrom supporting the container for theliquid to be sprayed and having passages connecting the container withthe cylinder sleeve, and a locking ring rotatable on the one-piece partthreaded in said bore of the housing releasably securing said one-piecepart to said housing.
 9. The spray gun of claim 8 wherein the portion ofthe one-piece part insertable in the bore of the housing has a front endprojecting from the housing and a spray nozzle is removably secured onsaid front end.
 10. A one-piece cast or molded part for removableattachment to the housing of a spray gun having a supply container whichcomprises a member having a sleeve portion insertable in a spray gunhousing providing a pump housing and surrounding a pump cylinder sleevein integrated relationship therewith together with a depending neckportion suspending a lid adapted to receive and support the supplycontainer for the gun, said member having passages therethrough joiningthe interior of the cylinder sleeve with the interior of said lid, and alocking member on said one-piece part for detachably uniting the part tothe spray gun.